1. Field of the Invention
The present invention relates generally to methods for disposing of hazardous and non-hazardous waste. More particularly, the present invention relates to a method for disposing of absorbent material impregnated with waste, wherein the absorbent material is processed to release the waste so that it disperses and mixes with the material to form a mixture that may be disposed of in an industrial furnace or incinerator.
2. Description of the Prior Art
As environmental regulations for the transporting, storing and disposing of hazardous and non-hazardous waste become more stringent, it is increasingly important that methods for their effective and safe disposal be found. The disposal of many wastes is complicated in light of decreasing landfill space availability and the increasing demands on waste containment facilities. Even though greater efforts are being made toward the minimization of waste production, the demand for competent waste disposal methods and facilities continues to increase. Such demands on current disposal methods and facilities will likely continue to increase as more compounds are classified by the United States Environmental Protection Agency.
Wastes which are "bulky" in character place a particular burden on waste transportation, disposal, and facilities due to the inherent nature of such wastes to require increased handling efforts and increased disposal space. Bulky wastes include absorbent materials such as cloths, rags, paper and sponges. Many of these materials will also be fibrous. Such materials are used in a variety of industrial applications, such as cleaning of equipment, use with solvents or other chemicals, and wiping up spills of oil, paints, and other liquids. The absorbent materials, particularly industrial cloths, may be used to absorb or clean up gross hazardous or non-hazardous waste spills. Once a hazardous waste is absorbed into the material, it is often itself classified as hazardous waste.
Altering the physical characteristics of bulky wastes, such as the absorbent materials described above, can facilitate the transportation and disposal of such wastes. Several methods are currently employed for the reuse or disposal of absorbent materials, particularly used industrial cloths and rags, which have become impregnated with waste. In some instances, the rags are washed to remove the waste absorbed into them. The rags can then be re-used in industrial and other operations. However, this method is undesirable because of the increased handling of the used rags required during the cleaning process. Furthermore, the rags and cloths may be impregnated with waste which is listed by the United States Environmental Protection Agency as hazardous or which exhibits hazardous characteristics. Thus, the wash/waste mixture extracted during the cleaning process may itself have to be disposed of pursuant to environmental regulations. There is also some question as to the effectiveness of the cleaning process. Washing rags or cloths containing waste may not eliminate all residues, and workers may be exposed to such residues when the rags are reused. Rags, cloths and sponges impregnated with waste may also be mechanically "wrung-out" to remove the waste from the material. However, this method is subject to the same undesirable results as experienced when the rags or cloths are washed.
Industrial rags, cloths and other absorbent materials impregnated with waste may also be disposed of using biodegradation methods. The waste-impregnated absorbent materials are disposed of at containment facilities in the presence of microbes which biodegrade the materials and the waste. The process requires a long period of time, and a substantial amount of labor during the biodegradation process.
The primary method for disposing of waste-impregnated industrial rags and cloths has been to place them in landfills, or to incinerate them by traditional incineration methods or burn them in boilers or industrial furnaces ("BIF"). The waste absorbed into the rags or cloths may possess potentially high heat generating (BTU) values, and the rags and cloths themselves frequently have a high BTU content. The rags and cloths impregnated with wastes having high BTU values provide advantageous and economical fuel for various industrial purposes, such as use in BIFs.
Fuel flow requirements for incinerators and BIFs are often critical, and necessitate maintaining continuous optimum uniform temperature values, depending on the amount of heat required. Optimum combustion efficiency can be achieved by feeding an incinerator or BIF a continuous flow of a waste mixture. Therefore, the mixture should be of a consistency that can be steadily and evenly fed or pumped into the incinerator or BIF.
Absorbent materials have been chopped or shredded at disposal or blending sites prior to feeding the materials into an incinerator or BIF. However, chopping or shredding absorbent materials produces a product of uneven consistency which does not readily feed into a BIF. A steady stream of waste material is desirable for accomplishing complete combustion and temperature maintenance within a BIF.
Shredded absorbent material may be blended with water or other liquids to facilitate feeding material continuously into an incinerator or BIF. For example, shredded rags or other absorbent material, may be blended with hazardous liquids having high BTU values. The high-BTU liquids enable blending, and provide the temperature values necessary for efficient and complete combustion of the materials in the incinerator or BIF. However, the course nature of the blended mixture makes the mixture difficult to handle and manipulate. Further, the pieces of material tend to settle out of the blended mixture when feeding the mixture into an incinerator or BIF.
Difficulties experienced with disposing of absorbent materials impregnated with waste were partially addressed by Costello et al., U.S. Pat. No. 4,715,300, dated Dec. 29, 1987. Costello et al. provided a method of disposing of waste-impregnated materials, primarily industrial rags and cloths, by dissolving the materials in acid and then incinerating the acid mixture. Preferably, the acid mixture would be incinerated in the incinerator of an acid regeneration plant. Although the method revealed by Costello et al. produced a slurry or nearly liquid product capable of being fed to an incinerator, the materials impregnated with waste must be acid-dissolvable. Further, preparation of the mixture and the subsequent handling of the acid mixture requires substantial labor and safety controls.
It is therefore an object of this invention to provide an improved method of disposing of absorbent materials impregnated with waste which overcomes these and other problems with prior methods for this purpose.